1. Technical Field
The present invention relates to a liquid composition, a pigment dispersion liquid containing the liquid composition, and an aqueous ink composition for ink jet recording.
2. Related Art
Since an ink jet recording method is performed using a relatively simple device and is capable of recording a high definition image, rapid development thereof has been achieved in various fields. However, in a case of the aqueous ink composition (hereinafter, simply referred to as “ink”), microscopic organisms may be propagated during storage. If the microscopic organisms are propagated in the ink, it is likely that pH of ink is decreased, sedimentation of the ink component occurs, and deterioration of the ink or clogging of a nozzle occurs. In order to solve these problems, various studies for antiseptic properties of the ink have been conducted.
For example, JP-A-2011-46624 discloses that 1,2-benzisothiazolin-3-one is used as an antiseptic and antibacterial agent which is used for the liquid composition. In addition, for example, JP-A-2003-183558 discloses that Proxel XL2S is mixed into an aqueous pigment ink for ink jet as an antiseptic and antifungal agent. Further, JPA-2010-222417 discloses an aqueous ink composition which is obtained by heating a pigment dispersion liquid which contains sodium benzoate and the like as an antiseptic agent and an antifungal agent, and a glycerin ether compound as a humectant.
However, the antiseptic and antifungal agent has biocidal activity, and thus, in a case where a label printing and a textile printing are performed by using the ink containing the antiseptic and antifungal agent, skin sensitivity may be caused depending on how the ink was treated when a printed matter comes into contact with the skin. For example, since the minimum inhibitory concentration is in a range of several tens of ppm to several hundreds of ppm with respect to microscopic organisms of the antiseptic and antifungal agent, the concentration at the time of adding the ink is approximately 500 ppm at most, and the safety of ink itself is high. However, the antiseptic and antifungal agent is concentrated on the printed surface after the liquid component is separated through the printing, and thus, the concentration becomes 10 to 20 times greater as compared with the case of adding the ink.
The antiseptic and antifungal agent has low volatility for retaining the antiseptic properties and low redissolvability after being dried, and thus, is likely to remain on the printed surface. Accordingly, for example, in a case where a printing base material is formed of a film, the concentration of the antiseptic agent on the printed surface is likely to be high, and in the case of performing label printing and textile printing, the ink easily comes into contact with the skin when handling the printed matter, and thus, for the purpose of the above operations, there is a risk of allergic contact dermatitis being caused due to skin sensitivity. Therefore, ink with high safety has been required.
Further, the glycerin ether compound which is mixed in JP-A-2010-222417 has a high distribution coefficient of water-octanol, and is a water-insoluble compound, and thus, the glycerin ether compound is easily separated from the liquid composition. For this reason, if the glycerin ether compound which is mixed in JP-A-2010-222417 is used, ink stability may not be obtained at a low temperature, or ink discharge may not be stable. Thus, if a glycerin ether compound having a low distribution coefficient of water-octanol is used, there is a possibility that an effect as the antiseptic agent cannot be obtained.